As a Marine
by Damnthenamedoesntfit
Summary: Seven years before Ace was born, Dragon had a daughter. Her name was Monkey D Kirito, and she was the elder sister of Monkey D Luffy.
1. Chapter 1

Sengoku was understandingly more than a little surprised when Garp came barging into his office one morning screaming 'I'M A GRANDPA!' As far as he knew, Garp only had one child, and if he was a grandfather, his grandchild would have to be the child of Garp's child. Which meant that his grandchild was the child of Monkey D Dragon. Which was not good.

After much of Sengoku's inner panicking and voicing some of his troubled thoughts, Garp had the audacity to laugh and reassured him that no blood of his wouldn't become a marine.

 _'_ _That's what you said about Dragon,'_ Thought Sengoku darkly. He decided to let this one go for once, he had much more pressing matters to address. Namely that blasted Pirate King who was running around the grand-line. Not to mention that Whitebeard was also terrorising some poor marine warship. Garp's grandchild could wait.

* * *

Five years later and with Roger finally executed-starting the great age of pirates, the bastard- Sengoku could no longer ignore Garp's grandchild's existence. His old friend had eagerly shoved a child into his office two days after the request to meet them. Surprisingly, she was female.

Monkey D Kirito did not look anything like Garp or Dragon. With a startling head of long midnight blue hair, cerulean eyes and pale skin, yes- she did not look anything like her family. Garp had shrugged and said 'it's probably from her mother's side.' Did Garp ever meet the woman who had managed to capture his son's fancy? No, and probably won't ever.

Somehow, Garp had managed to get her strong enough to beat an average marine, probably through borderline child abuse training. When Garp explained her ridiculous training regiment, Sengoku pitied the poor girl. One does not get thrown off cliffs for casual training. She even managed to eat a devil fruit along the way, the Speed Speed no mi. The brat was quick.

Even with all the rather lethal training from her grandfather, Kirito did not really mind the thought of being a marine…but she didn't care about being a pirate either. With this in mind, Sengoku decided that it was okay to let Monkey D Kirito roam free. She would be a great asset to the marines, he just hoped to god that she wouldn't cause too much collateral damage when running around and doing whatever. Marine HQ could not handle another Garp, no matter how useful they were.

Sengoku doubted that a five year old could do too much damage, but then again, this was _Garp's_ grandchild. D's did have a tendency to be rather unpredictable…like that time when Garp traded the whole treasury for a box of doughnuts. Sengoku was rather startled when he learned that Garp dragged his granddaughter around with him on the grand-line. The grand-line was no place for a child, much less the New World.

So yes, Monkey D Kirito would be an excellent marine.

* * *

Garp had promised Roger that he would look after his son. After all, he knew what it would be like for little Ace if the world government ever knew of his existence. They would be calling for his blood, telling them to execute an innocent child. Kirito was a prime example. She had no protest about being a marine, and that was probably the only reason-along with Sengoku's vouch for her about being an asset-why she wasn't already on the chopping block. So Garp told Roger that he would adopt Ace after he was born. It was probably a large reason why Roger died with a huge grin on his lips.

Kirito was there with her grandfather when Portgas D Rogue gave birth. With Ace cradled in her arms, Rogue waved the seven year old closer. After getting a nod from her grandfather, she stepped closer to the weak woman. Rogue gave Kirito a gentle smile and beckoned her even closer. She took hesitant steps to the woman until she was standing right beside her bedside. She handed Ace over to the startled girl.

"His name is Ace," Rogue said, rearranging Kirito's arms to accommodate the baby. "Will you be a good big sister and look after him for me?"

Kirito nodded, "I promise I'll be the best big sister ever." And that was a promise she was going to keep. Rogue smiled at her with watery eyes.

"Thank you." She kissed Kirito on the cheek and kissed Ace's forehead one last time before her strength faded, and she finally died with a smile on her face. The doctors and nurses rushed forwards, trying to save the dying woman but to no avail. As if sensing that his mother was gone, little Ace started to wail. Kirito clutched him closer to her chest, and started to rock him back and forth.

"Shh, nee-chan's here. I'll protect you."

Kirito spent the next few years running around the grand-line with her grandfather and visiting Ace in her free time. She spoilt him with love and toys. When Luffy was born and dropped off at Foosha Village with Makino, she had to split her free time in half. Adding her fast ascension in the marine ranks, missions and training at HQ, she hardly got to visit either of her beloved brothers. Kirito would still make time for them though, and she still loved them.

* * *

Sengoku rubbed the bridge of his nose in exasperation as another explosion went off. Marine HQ was starting to get used to it. An unhealthy get-used-to-it way like someone would get used to eating dinner with cannon balls exploding above their heads-and during some days, that actually happened. Kirito was now seventeen, and she grew to be quite a beauty with many admirers at HQ. And strong, very strong. She had apparently inherited Garp's superhuman strength that was both a blessing and a curse. Kirito was promoted to Vice-Admiral not too long ago.

In the large training courtyards, that bastard Garp and his granddaughter were playing baseball with the new recruits.

With cannon balls.

It was Marine HQ's new way of dealing with cocky new recruits and to knock them off their high horses. Sengoku almost had a heart attack when Garp first taught ten year old Kirito how to throw cannon balls with her bare hands. And by god it was _terrifying_. The first few hours in the courtyard were more dangerous than the Florian Triangle. Marines had to constantly duck and dodge stray cannon balls until Kirito's accuracy improved. The unlucky marines that weren't quite fast to dodge spent weeks in the infirmary. Garp's obnoxiously loud laughter filled with pride did not help the situation.

Someone had jokingly suggested that a ball game with Garp and Kirito would prove that recruits more were than worthy. Unfortunately, it was taken the wrong way, and the survivors of the games were directed to the dumbass that spoke of hell on earth so casually. The games ranged from cricket, baseball, volleyball and the especially lethal dodge ball. It certainly wiped out the weaklings.

The games became even more dangerous as Kirito went through puberty. There were now special rules installed to save the poor souls (or salvage the ones with potential) who participated in these games.

1) Do not ogle Vice-Admiral Kirito. She may be oblivious to your lecherous stares and pick up lines, but her over-protective grandfather certainly isn't. Her pretty face isn't worth it.

2) Do not gloat at either Vice-Admirals if you manage to somehow score a point. You will get a face full of cannon balls, and your team will pay for the man shaped hole in the wall. They will also congratulate you for that scored point, even if it was a fluke.

3) Do not get Vice-Admiral Kirito angry when it's _that time of the month_. She will throw harder, faster and more accurately. Not only would you be sent to the infirmary, but so will your entire team. She does not discriminate.

4) If Vice-Admiral Garp takes off his dog hat, _run away_. He will get serious (which hardly ever happens) and he will use the _big ball_ (the one about the size of his warship) Proceed to pray to god that you will survive. Then thank the gods that Vice-Admiral Kirito cannot throw that one yet (it has been noted that it's Garp's special ball, that he uses only when you _really_ piss him off. Like when you hit on his granddaughter.)

5) Do not attempt to bribe them with food. It only works on Vice-Admiral Garp, and Vice-Admiral Kirito does not like cheaters. She _will_ attempt to kill you throughout the entire game, even if you had a deal with her grandfather.

6) If you are a logia, stay tangible. They will only coat the cannon balls with Haki, and that hurts _a lot_ more.

7) Congratulate yourself. You have somehow managed to get yourself in this fucked up mess.

The survivors were tearfully handed a medal of bravery, and had the respect and admiration of the senior marines accepted before the games were played at HQ. Surviving a game against the Monkey D's was not easy.

* * *

"Was it good that I was born?"

The question had caught Kirito off guard. She sat with crossed legs, a ten year old Ace in her lap and playing with her long hair. They were sitting on the cliff near Dadan's hut. Kirito was out of uniform, wearing a black tank top and jean shorts.

"Why do you ask that?" She asked resting her chin on top of Ace's head and wrapping her arms around the freckled boy. He shrugged.

"Everyone says so. They think I'm a demon child." Ace paused, and a sound of hurt entered his voice. "I bet you think so too."

She sighed. Ace took this as a confirmation, and tears gathered in his eyes. He knew it. He knew his sister hated him too. He knew that-

"Ace. Do you think it was good that I was born?" This question startled him.

"Of course! You're my big sister! You're nice, you played with me when nobody else did. You took care of me when I was sick. You taught me how to hunt and you patched me up after gramp's training. Even the bandits like you!"

Kirito laughed. The chest that Ace was leaning against vibrated along with his big sister's laughter. "Well then!" She turned Ace around on her lap so that he was facing her. She poked him on the nose. "You're my little brother. You're smart, you're fun and you beat up the guys that looked at me funny. You hunt with me, you make me laugh and smile. Of course it was good that you were born!" And by the end of it, she was tickling his sides as Ace shrieked with laughter. After a minute, Kirito stopped.

"Ace. Do you know who Nico Robin is?" Ace shook his head. Kirito hummed and wrapped her arms around Ace tighter.

"She's just like you Ace. Lots of people call her a demon child." Ace's eyes widened. Someone like him? "She was already wanted by the government when she was eight. She's still on the run, just because she knows how to read an ancient language." Ace was quite shocked.

"Just because she could read an ancient language?" He echoed. Kirito nodded.

"You see, there are lots of us 'demon children' out there, but some of us are hidden much better than others." Ace nodded in understanding. Then he froze.

" _Us_?"

"…Oops. I wasn't meant to say that." She muttered. "Oh well. Cat's out of the bag. It's not like I could keep the secret for much longer anyway."

"What secret?" Ace asked confused.

"Oh, you know. It's nothing much. Just that my father is currently the most wanted criminal in the world." Kirito said nonchalantly.

" ** _WHAT_**?!" Ace whipped his head around, a bewildered look on his face. "You're…!?"

"Uh-huh,"Kirito nodded. After a moment, she said, "Listen, Ace. The sins of our fathers don't make us who we are. You are your own person." She poked him in the chest. "Some people will keep comparing you to your father, so you have to step out of his shadow. If you want to be acknowledged, if you don't want to be known as the son of a demon, become Portgas D Ace. Become famous, make a name for yourself."

Ace took these words to heart. He buried his head in the crook of her neck, trying to hide the tears in the corner of his eyes as she stroked his hair. Someone just told him that they didn't care about who his father was. Someone didn't hate him. They stayed that way for a several long minutes. Ace finally asked a question that had been bothering him for so long.

"Why did you become a marine?" Kirito smiled at him, amusement in her eyes.

"I'm a demon child, Ace. Grandpa was already bragging about how I would be a great marine before I could walk. He forgot to keep his mouth shut. I guess that if I wanted to be anything other than a marine, they would kill me before I become a threat. They're only letting me live because Grandpa's a hero. But you…they don't know about you. Gramps didn't say anything about you yet. You can be whatever you want to be."

Ace thought long and hard. There was no way in hell that he was becoming a marine, which only left one option. He was going to be a pirate. Ace was going to be a famous pirate, so everyone would know his name. He was going to be free. If not for himself, then he would do it for his big sister who never had a choice.

* * *

 **Leave a review and tell me what you think ;)**


	2. Chapter 2

Higuma was an arrogant man who usually got he wanted.

That included beautiful women. Beautiful women like Kirito.

The bluenette was visiting Ace and the Dadan family and was on her way back to her ship to pick up something for Luffy before heading to Foosha village. Higuma couldn't help himself when he saw a pretty girl walking alone in the jungle. She was exotic, her pale skin and blue colouring a rarity in the mountains. She would do nicely with the other women he had collected over the years. He had been in a sour mood ever since the cowardly pirates drained the sake in the local village.

"Well, well, well. What do we have here?" He drawled while stepping out from the trees. Kirito gave him a blank look and ignored him, side stepping Higuma and continued on her way. His henchmen gaped at the girl that brushed off their boss. There was no doubt that Higuma would get angry.

"Oi! I'm talking to you!" Higuma growled, marching over to Kirito and grabbing her arm. Higuma expected the girl to cower. He expected her to flinch and beg for mercy. He expected her to run.

But Higuma did not expect to be eating dirt.

He blinked, trying to piece together what had just happened. With his face pressed to the ground, Kirito sat on top of him with his arm twisted painfully in a grip of steel. Cold cerulean eyes stared into his soul.

"Don't touch me," She growled.

Instead of being a normal person and acknowledge that it might be the best idea to mess with a person who could pound him into the earth, Higuma refused to be beaten by a girl (that severely outclassed him).

"Get her!" He snarled from his subdued position. His followers charged.

It started raining men.

* * *

Makino had served many unusual people as a bartender. Garp the fist, and Red haired Shanks were a few examples. But bandits that looked like they had their asses handed to them? That was new. And it wasn't just any group of bandits either. It was the same group that came by the day before. They probably would have been intimidating if they didn't look like they had jumped into a blender.

"We're customers woman! Bring us sake!" A bruised Higuma mumbled through a split lip.

"Right away sir," Makino replied. She looked at him in concern. "Um…are you okay?"

Higuma just glared at her.

"You're the guys that made fun of Shanks!" Luffy stood from his spot on the bar stool. "You better apologise to him!"

"Luffy!" Makino admonished. She didn't want anything to happen to him because he taunted the wrong person.

The bandits just gave him an irritated look. "And why should I apologise to weak, cowardly pirates?"

"Shanks isn't weak or a coward! You better take that back you baboon faced idiot!" Luffy yelled, quick to defend Shank's honour despite being mad at him a few minutes ago.

"What did you say punk?!" Higuma growled. The other bandits in the bar started to grip their weapons.

"I said you're a baboon faced idiot!"

Ignoring his battered body, Higuma grabbed a struggling Luffy by the back of his shirt and lifted him up.

"I think that you better be taught a lesson."

* * *

Kirito had already grabbed the small box for Luffy and was on her way to the Party Bar when she spied a crowd at the docks.

"What's going on?" She asked the nearest man.

"It's Luffy!" He said, and Kirito's blood ran cold. "He messed with bandits and they've taken him hostage!"

She looked out to the ocean and saw the same bandit she met a few hours ago in a boat, holding her baby brother by the throat over the water. White, hot fury boiled in her veins. _No body_ hurts her family.

"Hold this," she snapped, shoving the box in his arms and pushed her way to the front of the crowd. "Give me a cannon ball!" Kirito growls at the pirate standing next to her, recognising Benn Beckman.

"We won't be able to get a cannon ball in time," He said to the Vice-admiral, already knowing what she wanted to do.

"Then give me a sword!" Kirito looks back over to see the Lord of the Coast hovering over Luffy. "Give me a sword _NOW!_ "

Seeing his captain and Luffy in a precarious position, he snatches a sword from his fellow crew mate and hands it over to her. As soon as the handle is in her grasp, Kirito hurls it as hard as she could at the sea king. The blade embedded itself into the sea king's eye, and it recoiled in pain, it's teeth inches away from sinking into Shank's arm. The Lord of the Coast roars in agony, and swims away to heal its wounds.

With threat gone, Shanks grabs Luffy and swims to shore, with thankfully both arms. He hauls himself into the dock with a crying Luffy in his arms. Ignoring the fact that Shanks is a pirate, she races over to the pair, throwing her arms around both of them and kisses a soaking wet Shanks on the cheek.

"Thank you, thank you, _thank you_!" She kisses him each time she thanks him. Kirito then, gently lifts Luffy into her arms, wiping away his tears.

"It's nothing," Shanks said sheepishly, rubbing the back of his head. A 'lucky bastard' was murmured somewhere in the crowd and was soundly ignored.

"You might be a pirate, but I owe you. If you need a favour, just call me." Kirito said, handing over her Den Den mushi number, cradling Luffy in one arm.

Shanks gratefully accepted the number. "It's no problem. Anything for a friend."

* * *

As the Red Force departed from Foosha Village, Luffy-with his new hat-stood at the dock waving until he could no longer see the ship. Kirito stood next to him, a hand on her brother's shoulder.

"Since you have that nice hat, I don't think you'll like my present anymore," She playfully teased. Luffy perked up from his dull mood at the mention of 'present'.

"Present?! Can I have the present?" He grinned excitedly. Kirito smiled, holding out a box to him. Rubbery hands grabbed to box and ripped off the lid.

"Ne, Nee-chan what is this?" He asked, holding out two pieces of black fabric. Kirito took the fabrics and slid one up his elbow and the other on his opposite knee.

"These are elbow and knee guards," She explained, lightly tapping the hard surface at the joint of his elbow. "Since you get hurt a lot during Grandpa's training, I thought that I would give you my old pair. I used to wear this when Grandpa was training me. It makes it hurt less."

She had already given Ace the other half of her set.

"Thanks Nee-chan!" Luffy beamed. "Why is it so heavy?"

"It's training as well, so you can get faster and stronger when you take it off." Kirito didn't mention that the steel caps were actually thinly coated in sea stone and weren't that heavy to a normal person. It would train Luffy to become slightly more resistant to sea stone and sea water. It also served as something to hit a devil fruit user with.

"Don't take it off unless you are in really deep trouble, okay?"

"Okay Nee-chan!"

* * *

It was another few months before Garp picked Luffy up to go to Mt Corvo.

"But I don't want to go!"

"What did you say brat?!"

Two figures walked down a path deep in the jungle on Dawn Island. One was a tall man with broad shoulders, dressed in a black suit with grey hair. The other was a pretty woman dressed in a casual t-shirt and shorts, with long midnight blue hair.

Kirito held onto a clinging boy who wrapped his entire body around her torso like a snake, his rubbery hands sticking close to the woman as possible. Luffy knew that his grandpa wouldn't hit his elder sister unless training, and he was going to take advantage of this as much as possible. Kirito was a nice sister anyway, just as nice as Makino.

Garp clenched his fists, but restrained himself from smacking the shit out of his grandson. Kirito walked along with a serene expression on her face, never seeing Luffy poke his head over her shoulder and stick his tongue out at their grandfather. Garp inhaled through his nostrils.

 _Can't join the marines if he's dead. Can't join the marines if he's dead. Can't join the marines if he's dead._

Garp exhaled.

"I'm gonna be Pirate King!"

Luffy was pried off Kirito and punched through the forest.

* * *

Soon enough, the trio reached the Dadan family hut.

"Dadan open up!" Garp yelled, banging hhis fist against the wooden door.

The door slammed open. "Who dares to-! Oh it's you."

An orange haired bulky woman stepped out from the hut, a cigarette between her lips. "What do you want? Is that another brat?!" Dadan asked irritated, spotting a bruised Luffy in Kirito's arms.

"That's right! This is my grandson Luffy. You gotta take care of him as well," Garp stated with crossed arms. Kirito set Luffy down and let him explore his new surroundings.

"He better not be too much trouble, and I want payment! Keeping brats is costly you know!"

As Garp and Dadan haggled over money, Kirito watched Luffy chase a butterfly. Her blue eyes shifted over to the bushes when Ace emerged, dragging a dead buffalo. As soon as he saw her, his face brightened and he dropped his metal pipe and his kill.

"Kirito-nee!" He attacked her with a flying hug. She caught him with an 'Oof', his sea stone elbow guards making her slightly weak.

"Hello Ace," She responded with a smile. "How are you doing?"

"Good!" He grinned, clinging onto one arm. "Those elbow and knee guards you gave me work great! Did you know I elbowed a crocodile? It was awesome!"

"Oh Ace! You're back!" Dadan called, momentarily ceasing her argument with Garp. "What did you catch this time?"

"Buffalo," He answered, his eyes only now registering the other people in the clearing. His dark eyes darted to Luffy, and settled on familiar elbow and knee guards. Jealousy seized his heart, but Ace shoved the feeling into the corner of his mind.

"Who are you?" He asked the straw hat wearing boy.

"I'm Monkey D Luffy! Who are you?" Ace held onto Kirito a little tighter.

"I'm Ace, I'm Kirito-nee's _brother_."

"What are you talking about? _I'm_ Nee-chan's brother," Luffy barks defensively, he stretches his arm to wrap around Kirito's vacant arm.

"No, _I am!_ "

"Are not!"

"Are too!"

"ARE NOT!"

"ARE TOO!"

 ** _"_** ** _SHUT UP!"_** Garp slamed his fist down on both their heads, clamping their jaws shut. "You're both her brothers! Which means you're brothers as well, so you better get along! Am I understood?!"

Luffy and Ace just rubbed their heads and glared at each other.

* * *

 **If you're wondering why Dadan is nicer, it's because Ace isn't causing chaos just to spite them for calling him a demon child. Kirito has already told him that she doesn't care about his heritage, and neither does Sabo. There might be sibling rivalry in the next chapter.**

 **Anyways, leave a review on your way out and tell me what you think ;)**


	3. Chapter 3

**Got a massive writing block. I managed to conjure something up for the meantime.**

* * *

 **As a Pirate**

 _In which, the eldest daughter of Dragon never became the marine that her grandfather wanted her to be, and goes gallivanting off around the Grand-line as a pirate. (As a Marine AU)_

* * *

" ** _No blood of mine won't become a marine_** you said. **_Dragon was a strange child, but there's no way Kirito will leave me!_** you said. Then what is _this_?!"

Sengoku slammed the newest issued bounty onto his desk in front of a catatonic Garp. The picture showed a young woman standing on top of a pile of defeated marines, one gloved hand holding onto the brim of her black cap on top of her head and the other in the pocket of her pants. Blue eyes stared mischievously at the camera.

The Fleet Admiral of the Navy shouldn't really be surprised that Garp's offspring turned out the way they were. Garp's near fanatical 'training and brainwashing' for installing the marine mindset turned into 'torture and brain-bashing'. His child rearing abilities (if they could even be called that) seemed to turn whomever he raised _away_ from the 'Justice' motto rather than _to_ it. Just look at Dragon – he somehow got it into his head that the world needed a revolution, and he gained a loyal merry band of followers who seemed to do everything in their power to topple the Wold Government. The world already had three powers of balance, but Dragon's revolution wanted to flip the bloody scale and plant itself into a system that was working just _fine_.

Sengoku didn't even know why he expected any better when another criminal descendant of Garp made her way into the world at large. At this rate, Garp's other grandchildren – including the other two boys he adopted (the poor things) and his own biological grandson – would become anything _but_ marines. Sengoku was half convinced that the three would join their 'father' in the revolution or start sailing the seas like the chaotic vagabond their sister was. Either way, the marines had better start preparing for the shit-storm that was coming in about a decade give or take.

Ever since he heard the news, Garp dug himself into an extremely deep pit of depression that Sengoku almost doubted that he would ever get out of. It was the exact opposite of the reaction that the Fleet Admiral was expecting. When Dragon abandoned his father, Garp went on a rampage that almost crippled his son's journey as the 'most wanted criminal alive' before it even began. The depression didn't last long when Garp came to the conclusion that his 'sweet darling granddaughter' Kirito was kidnapped and forced to engage in breaking the law and assaulting marine bases and ships.

("Look at how terrified she is! Don't worry darling, Grandpa will come save you!"

"Does she _look_ like she's terrified?!")

The problem, was that Monkey D Kirito was as slimy and as hard to catch as her father, darting around the seas and destroying ships and buildings with the ease of her grandfather.

The level of denial that Garp seemed to be drowning in was a bit concerning. It came to the point where the idiot started crossing off the 'WANTED' and scribbled 'MISSING' over her bounty poster, before waving it around Marine HQ, asking passing officers if they had seen her.

At his rather spectacular track record of raising children, Sengoku was waiting for three more bounty posters in the next ten years.


End file.
